Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 6In this example, the linear growth model for a continuous outcome atfour time points shown in the picture above is estimated.TITLE:this is an example of a linear growthmodel for a continuous outcomeThe TITLE command is used to provide a title for the analysis. The titleis printed in the output just before the Summary of Analysis.DATA:FILE IS ex6.1.dat;The DATA command is used to provide information about the data setto be analyzed. The FILE option is used to specify the name of the filethat contains the data to be analyzed, ex6.1.dat. Because the data set isin free format, the default, a FORMAT statement is not required.VARIABLE:NAMES ARE y11-y14 x1 x2 x31-x34;USEVARIABLES ARE y11-y14;The VARIABLE command is used to provide information about thevariables in the data set to be analyzed. The NAMES option is used toassign names to the variables in the data set. The data set in thisexample contains ten variables: y11, y12, y13, y14, x1, x2, x31, x32,x33, and x34. Note that the hyphen can be used as a convenience featurein order to generate a list of names. If not all of the variables in the dataset are used in the analysis, the USEVARIABLES option can be used toselect a subset of variables for analysis. Here the variables y11, y12,y13, and y14 have been selected for analysis. They represent theoutcome measured at four equidistant occasions.MODEL:i s | y11@0 y12@1 y13@2 y14@3;The MODEL command is used to describe the model to be estimated.The | symbol is used to name and define the intercept and slope factorsin a growth model. The names i and s on the left-hand side of the |symbol are the names of the intercept and slope growth factors,respectively. The statement on the right-hand side of the | symbolspecifies the outcome and the time scores for the growth model. Thetime scores for the slope growth factor are fixed at 0, 1, 2, and 3 todefine a linear growth model with equidistant time points. The zero timescore for the slope growth factor at time point one defines the interceptgrowth factor as an initial status factor. The coefficients of the intercept102